FILICES.

Bracken (Pteris aquilina L.). The Bracken, Brake Fern, or “Fern” is of very considerable importance to farmers for four reasons: (1) It is a most pernicious weed; (2) it forms an excellent litter for stock and treads down into good manure; (3) it is said to have been successfully converted into silage; but (4) it has been accused of poisoning cattle.

In regard to possible poisonous properties, it must be said that the facts are at present somewhat uncertain, but a number of authorities clearly regard the Bracken as poisonous. (a) Müller (1897) records the poisoning of horses which ate it for some weeks with chaff—and some died. (b) Chesnut and Wilcox (1901) say that cases of poisoning of horses and cattle have been reported from England and a few localities in the United States. (c) Pott states that when eaten in quantity by cattle Bracken causes hæmaturia, and in horses nervous symptoms (brain trouble), sometimes with fatal effects. (d) Pammel also remarks on the believed poisonous character of this plant. (e) In view of its suspected poisonous character feeding experiments were conducted by the Board of Agriculture and Fisheries with a large quantity of Bracken, but the results were negative, yielding no experimental proof of the plant being poisonous. One animal—a heifer—consumed 60 lb. of Bracken between Aug. 14 and Aug. 20, and after two meals containing about 30 lb. of Bracken showed only symptoms of indigestion. After the 60 lb. there were no symptoms of illness. It has been thought possible that the so-called Bracken poisoning is due to Potentilla Tormentilla (q.v.).

In 1893 Storrar dealt with the question and expressed the view that any disorder due to Bracken was probably not a toxic effect but a digestive trouble simply (Jour. Comp. Path., 1893).

Toxic Principle. Continental authorities say that Bracken contains the poisonous Pteritannic acid, which is identical with the Filicic acid of the Male Fern (Aspidium filix-mas).

Symptoms. In the cases of horses which died Müller gives the symptoms as timidity, slower movement or action, loss of balance, dilated pupils, reddening followed by yellowing of the conjunctivæ, and slowing of the pulse.

Pammel notes Bracken as an astringent and anthelmintic, and also says it causes enteritis, spasms, and paralysis.

REFERENCES.

[10], [25], [57], [190], [203], [204], [213].

FUNGI[[6]].

Ergot (Claviceps purpurea). This fungus, parasitic on rye and a number of grasses, has long been known to induce distinct poisonous effects on man and domestic animals when ingested in sufficient quantity.

[6]. Poisonous parasitic fungi generally are not dealt with in this volume, but ergot is included because it is widely distributed and perhaps the best known, while its effects have been fully studied.

Ergot must be regarded as a cause of abortion in cows, though somewhat divergent views have been expressed as to the facts, some authorities considering the belief well founded, while others consider that there is little ground for it. It is quite clear, however, that when taken in sufficient quantity Ergot induces serious poisoning of domestic animals. Horses have died in two or three days from eating ergoted hay and wild rye. Extensive outbreaks of ergotism have occurred in the United States, and serious losses have been recorded in the Central and Western States. Ewart remarks that “a comparatively small number of fresh Ergot grains suffice to injure or kill a horse, cow, or sheep.” The effects of the poisoning of animals will be found under Symptoms below.

Toxic Principle. Ergot of rye is used in medicine. It contains 0·20 to 0·25 per cent. of Ergotinine. In the British Pharmaceutical Codex, 1911, the grains (sclerotia) of Ergot (see Frontispiece) are described as longitudinally furrowed, 1 to 4 cm. long, slender, curved, tapering to both ends; they break with a short fracture, and are somewhat triangular in transverse section; they have a characteristic and disagreeable odour and taste, are dark violet to black in colour, and whitish within. Ergot contains the physiologically active alkaloid Ergotoxine or Hydroergotinine (C35H41O6N5), also known as amorphous Ergotinine, and, when formerly obtained in an impure state, as Cornutine and Ecboline. It is the hydrate of the crystalline base Ergotinine (C35H39O5N5). There are also other physiologically active constituents derived from amino-acids.

Symptoms. In man Ergot has induced two types of epidemic ergotism, caused by the prolonged use of ergoted rye bread. The two forms are rarely or never found together. One is a gangrenous form characterized by agonizing pain in the extremities, followed by dry gangrene of the peripheral parts of the body. The second type of ergotism is much more rare—a nervous epidemic characterized by paroxysmal epileptiform convulsions.

Owing to the fact that at the outset ergotism causes irritation in the hands and feet it is termed “Kribbelkrankheit” in Germany.

The three substances noted above as isolated by Kobert are stated to cause poisoning—the first producing inflammation of the serous and mucous membranes, disintegration of the red blood cells, and widespread ecchymoses; the second excites the central nervous system and causes general convulsions; and the last induces gangrene.

In one case a horse ate ergoted hay: next day the left hind leg was stiff, and moist with cold sweat; on the second day it was badly swollen and gangrene of all the tissues became apparent, and after the skin of the leg and a considerable part of the muscular tissue had sloughed off the animal died on the third day. In other cases horses showed symptoms twenty-four hours after eating ergoted hay: fatigue, indisposition to work, cold sweat, particularly on the neck, paralysis of the tongue and muscles concerned in swallowing, and then generalized paralysis, very slow and deep respiration, subnormal temperature, normal pulse at first and then weaker till scarcely distinguishable, death in six or eight hours (Chesnut and Wilcox).

According to Pammel ergotism manifests itself among animals chiefly in the chronic form, the poison being acquired in small amounts and accumulation taking place slowly. Two distinct forms of the disease are recognized, the spasmodic and gangrenous. “Symptoms referable to the digestive tract, such as nausea, vomiting, colic, diarrhœa, or constipation occur in both forms. Pregnant animals very frequently abort.”

“In the spasmodic type of the disease, symptoms due to overstimulation of the central nervous system appear. These are tonic contraction of the flexor tendons of the limbs, anæsthesia of the extremities, muscular trembling, general tetanic spasms, convulsions and delirium. Death usually occurs from secondary causes.”

“Gangrenous ergotism is characterised by coldness and anæsthesia of the extremities, followed ultimately by dry gangrene of these parts. The effects of this dry gangrene are often very serious and amount to sloughing of the feet, tips of the ears, tip of the tail, shedding of the hair, teeth, etc. Death takes place from exhaustion.

“Acute poisoning is characterized by vomiting (in dogs), profuse salivation, dilatation of the pupils, rapid breathing and frequent pulse. The animal cries out, has convulsive twitchings, staggering gait, paraplegia, intense thirst and coma, terminating in death.”

In an extensive outbreak of ergotism in the United States in 1884 Law and Salmon reported as a prominent symptom ulceration of the mucous membrane of the tongue and mouth cavity, this and lesions on the extremities giving the appearance of foot-and-mouth disease. Affected animals showed weakness, dullness, and paralytic conditions of certain groups of muscles. When in pregnant animals the uterus is acted upon, labour pains occur, and the fœtus is expelled. The straining in those cases is often very painful and may be so severe that prolapsus of the uterus or even the rectum is the result. When Ergot produces gangrene, it usually affects the extremities, like the lower parts of the legs, the ears, tail or teats in cattle, and the comb, wattles, toes, wings or tongue of poultry. It is preceded by redness, coldness, and painful swelling of the parts affected. After a while sensibility of the dying region is lost and the line of demarcation between it and the living tissue becomes manifest. The dead portion commonly dies and is cast off. In some cases the gangrene is accompanied by symptoms of a septic nature.

“The possible result of the poisoning depends largely on the amount of Ergot taken and on the severity of the symptoms produced thereby. When small amounts are taken and only a slight dullness or digestive disturbance results the outlook may be quite favourable. Even Ergot abortion with rather severe symptoms usually is followed by recovery, but in the gangrenous cases, fatal terminations are common. The animals which through this cause have lost one or more parts are not only crippled, but septic or embolic complications may lead to a fatal termination. Paralytic cases do not permit of a favourable prognosis, especially if muscle groups containing important functions are involved.” (N. Dakota Exp. Sta. Rept.)

REFERENCES.

[1], [4], [13], [16], [35], [57], [81], [82], [128], [154], [161], [203], [242], [251].

CHAPTER VII
PLANTS SUSPECTED OF BEING POISONOUS.

A very large number of plants have at various times been suspected of possessing poisonous properties and causing harm to live stock. Of these it is quite probable that many are in practice entirely harmless, but some must be included as possibly deleterious, complaints having been made which vary in gravity from a slight irritation to causing death.

Purging Flax (Linum catharticum L.). It is perhaps doubtful whether this plant is really poisonous unless taken in considerable quantity by animals—as it is quite unlikely to be. It may, however, be included here, as it is stated to contain a glucoside which is purgative and which on fermentation yields prussic acid.

Furze or Gorse (Ulex europæus L.). In view of the fact that Gerrard isolated from the seeds of Gorse the alkaloid Ulexine, which is identical with Cytisine (p. [27]) and that the alkaloid is also contained in less quantity in the bark of young shoots, this plant has been suspected of possessing toxic properties. Experiments ([179])[[7]] with the alkaloid definitely showed it to be a nerve and muscle poison, 3 milligrammes having killed a chloroformed cat with convulsions in three minutes, though the animal could be kept alive as long as artificial respiration was kept up. As, however, Gorse has long been used very widely and in considerable quantities as a fodder the percentage content of the alkaloid must in general be exceedingly small, and no harmful effects need be feared from the consumption of the cut and bruised plant. Possibly the seeds might prove injurious if eaten in quantity.

[7]. Reference to Bibliography.

Melilot (Melilotus sp.) may at times cause injury. Ewart (82) writes: “All the species contain Cumarin, a volatile odoriferous principle, which in excess produces a disinclination to locomotion, paralysis and ultimately fatal symptoms. No harm is to be apprehended if the amount present does not exceed 10 per cent. of the herbage.”

Silver Weed (Potentilla Anserina L.). This well-known and elegant little weed is scarcely likely to be eaten to any extent by farm stock, though it may possibly be taken occasionally on roadsides. It has not been proved to be poisonous, but Pott states that it has a strongly constipating effect (213).

Tormentil (Potentilla Tormentilla L.). In relation to supposed bracken poisoning (see p. [87]) in regard to which experiments were conducted by the Board of Agriculture and Fisheries, Tormentil occurred in several instances with the bracken in localities where this plant was reported to cause poisoning. Two feeding experiments in which the weed was fed to heifers gave negative results. In a further case, however, 4 or 5 lb. were collected from a field where sick animals were grazing, and fed to a heifer; it appeared to be the cause of rise of temperature (to 106° F.), diarrhœa, and the passing of a considerable quantity of blood in the fæces for three days, after which the animal improved. It was, however, slaughtered, and lesions were found similar to those found in animals dying in the field from so-called bracken poisoning. Though the plant was suspected, results generally were not held to prove that it was the cause of poisoning (25). According to Van Rijn the root of Tormentil contains a considerable quantity of Chinovic acid (C32H48O6?).

Wall-Pepper (Sedum acre L.) is regarded as emetic and purgative, but to lose the harmful properties on drying.

Sundews (Drosera sp.) are reputed to be poisonous to sheep, but no evidence has been found.

White-Rot or Marsh Penny-Wort (Hydrocotyle vulgaris L.) is stated to have caused inflammation of the digestive tract, and hæmaturia; and to contain a toxic substance Vellarin (213).

Wild Parsnip (Pastinaca sativa L.). This plant has often been supposed to be poisonous, but Pammel shows that in Iowa the plant is quite harmless, as it appears to be in Britain.

Devil’s-Bit (Scabiosa succisa L.) is stated by Moir to have caused injury to cattle in one instance (Vet. Record, 1899), causing salivation, gritting of the teeth, twitching of facial muscles, and slightly protruded, abraded, swollen and sensitive tongue. An experiment on cattle showed the plant to induce violent inflammation of the mouth and tongue.

All-Heal (Valeriana officinalis L.) is not likely to be eaten by stock in sufficient quantity to cause poisonous symptoms, though it is stated to contain the poisonous Valerianic acid and Oil of Valerian. According to Chevalier (vide Henry) this plant contains an alkaloid not yet fully characterised.

Canadian Erigeron (Erigeron canadensis L.), sporadic in England, is suspected in America. It contains an oil, chiefly a terpene (C10H16). It has an acrid taste, causes smarting of the eyes, soreness of throat, aching of extremities, and colic; and irritation to people handling it (203).

Mayweeds (Anthemis sp.). It is not at all clear whether these plants are more than irritant in character, and they are so very common and widely distributed that there would probably be more evidence if they were poisonous. A. Cotula is regarded as suspected by Smith and Halsted, while Ewart says that it is obnoxious to stock on account of its unpleasant flavour, and if eaten by them in time of scarcity is apt to give their flesh, milk, or butter an unpleasant flavour. Güssow states that this species blisters the mouth and nostrils of animals. In his investigations at Kew, Greshoff found that the seeds of A. Cotula and A. arvensis contain much hydrocyanic acid. (He further found that the cyanogenetic glucoside from A. aetnensis Schouw. and A. chia L. belongs to the amygdalin type, giving off hydrocyanic acid and benzaldehyde on hydrolysis. “The strong odour of benzaldehyde may even be observed on grinding the seeds with water. Species of Anthemis contained from 0·15 down to 0·03 per cent. of hydrocyanic acid.”)

Cat’s-Ear (Hypochæris radicata L.). No record of poisoning of Cat’s Ear has been found, but it may be mentioned here, since Ewart says of it: “It contains a bitter, milky sap, which makes it unpalatable though not entirely poisonous.... An exclusive diet of this weed could not help but injure stock eventually.”

Dodders (Cuscuta sp.), when parasitic on clovers and fed as fodder or hay, have been suspected of causing digestive troubles in horses and cattle in the United States. Müller records a case of poisoning of young pigs by C. europæa, with inflammation of the intestines and nervous symptoms. Barbey determined the presence of the glucoside Cuscutin in C. Epithymum.

Viper’s Bugloss (Echium vulgare L.) is suspected of being poisonous; according to Friedberger and Fröhner it causes slavering (see also Cynoglossum).

Hound’s Tongue (Cynoglossum officinale L.). To what extent this plant is actually poisonous is not clear, but with some other members of the order (Echium vulgare, Anchusa officinalis), it contains the two alkaloids Consolidine and Cynoglossine—the former of which paralyses the central nervous system and the latter the peripheral nerves. (Greimer, 1900: vide Henry).

According to Hooker, Hound’s Tongue is narcotic and astringent, and Smith includes it as a simple vegetable irritant, causing nausea and purging. No records of actual poisoning of animals have been found.

Broom-rape (Orobanche minor Sutt.) has been suspected, and according to Boitel is liable to cause violent colic when it occurs in considerable proportion in clover and is ingested with it (73). On the other hand, in a case noted by Stapledon, in which Broom-rape (O. minor) had completely overrun the aftermath on a farm near Fishguard, two-year-old cattle devoured the plant with apparent relish and cleared off most of it in a few days after being turned in. The farmer stated that he saw no trace of colic or other ill effects. (Jour. Bd. Agric., September, 1916.)

Great Mullein (Verbascum Thapsus L.). Though it does not appear to be touched by farm live-stock the Great Mullein must be mentioned here. The leaves and flowers have been used medicinally as an emollient and pectoral, while the seeds possess narcotic properties and serve to stupefy fish (73). Pammel states that the plant causes irritation, but is probably not very poisonous to stock.

Toadflax (Linaria vulgaris Mill.). Cornevin describes Toadflax as acrid and poisonous, but says that stock reject it, and he could record no accidents to animals. In his full and excellent account of this weed, Kraus says it is regarded as poisonous, or suspected of being so, but that according to most accounts it is not harmful to cattle (168). Leunis regards it as suspicious on account of its acridity. Some German authorities say it is willingly eaten by cattle, but it is generally believed to be avoided, and owing to its disagreeable odour and acrid taste this view is probably correct. The plant has not been exhaustively studied, and while Smith gives the toxic principle as Oil of Snapdragon and the resin Gratiolin, it may be observed that Toadflax contains the glucoside Linarin (C64H56O40).

Figworts (Scrophularia nodosa L. and S. aquatica L.). These plants are not likely to be eaten by animals, but Cornevin states that the former is strongly emetic and purgative, and that in excess it may cause superpurgation ending in death. Müller says that the two species have respectively caused poisonous symptoms in a cow and a sheep; in the case of the cow there were loss of appetite and symptoms of paralysis. From S. nodosa Walz extracted a bitter, crystalline substance, Scrophularine.

Yellow Rattle (Rhinanthus Crista-galli L.). When grass land is put under the plough Yellow Rattle present may re-appear in a cereal crop as a semi-parasite, and its seeds may later be ground up with the grain, imparting a reddish or violet-brown colour and an unpleasant taste to the flour and even bread made from it. It is strongly suspected of being poisonous, like Pedicularis and Melampyrum, but it is by no means clear how far it may prove harmful to stock. It is believed by some people to impart a bad taste to the butter made from the milk of cows grazing on infested pastures. Lehmann ate without harm 35 grammes (about 1¼ oz.) of the seeds made into a cake and cooked; and during four days he gave a rabbit 1238 grammes (2·7 lb.) of the fresh plant with half-ripe seeds, without apparent injury (73).

In some poor pastures it occurs in excessive quantity, and would appear to be only very slightly poisonous, or would have attracted wider attention. It is possibly only poisonous after being eaten for a prolonged period, as in the case of Lolium temulentum, and Lathyrus sativus. The seeds contain the bitter-sweet glucoside Rhinanthin (C29H52O20), which is suspected of having poisonous properties.

Cow-Wheat (Melampyrum arvense L.). It seems clear that Cow-Wheat is at least not poisonous unless eaten in very considerable quantities—amounts in fact which in practice are most unlikely to be eaten. The seeds may occur in cereal grains, and hence be ground up into meal. As they are said to contain a glucoside analogous to Rhinanthin, have a bitter taste and peculiar odour, and impart a violet coloration to flour, their presence in cornfields is most undesirable. According to Pammel this plant induces sleepiness and colic.

Ground Ivy (Nepeta Glechoma Benth.) is, according to Schaffner, poisonous to horses. It contains a volatile oil and bitter principle, as also does Catmint (N. Cataria). In a case which came before the Board of Agriculture and Fisheries in 1906 three horses became ill with symptoms of poisoning, and the only weed found in the lucerne they were getting was Ground Ivy, and this was suspected but not proved to be the cause. In a further case, reported in 1909, eleven horses were believed to have been poisoned by this weed, and in one of the dead horses scarcely any food but Ground Ivy was found, and to it the veterinary surgeon in attendance attributed death. During preceding years several horses had died in the locality (Ely), owing, it was believed, to poisoning by the same weed. The losses, however, were not proved to be due to this plant.

In the Veterinary Journal (October, 1914, p. 515) poisoning of horses by this weed was noted (after Ferenczhazsy in the Recueil de Médecine Vétérinaire). The author observed nine cases of intoxication due to the weed, though it is stated that it “has occasioned no trouble in cattle and sheep that consumed it.” The symptoms in horses were “anxious look, dyspnœa, salivation, sweating, dilatation of the pupils, cyanosis, signs of pulmonary œdema.” Two horses died. In 1913 similar cases were observed by other owners, and terminated fatally.

Hooker states that N. Glechoma is “bitter and aromatic, formerly used for beer, occasionally for tea.”

Orache (Atriplex sp.). So far as known these plants are not poisonous, but it may be stated that Greshoff found the seeds of five species, and the leaves of two species, to contain a Saponin.

Nettles (Urtica sp.). Nettles are not generally regarded as poisonous otherwise than as causing painful nettle rash on the bare skin, but Urtica dioica L. is stated to have caused the death of dogs (Berliner Tierärztliche Wochenschrift, 1909).

Yellow Flag (Iris Pseud-acorus L.). The wild Flag was noted by Linnæus as dangerous to cattle, but no case of actual poisoning has been found in the literature. The plant is stated to have marked emetic and purgative properties, and Cornevin remarks that in Belgium intense gastro-enteritis is attributed to it. It contains the glucoside Iridin (C24H26O13).

Narcissus sp. Various Narcissi (e.g. N. pseudo-narcissus, N. poeticus, and others) have been regarded as irritant to the hands. They would rarely if ever be eaten by live-stock in Britain, but it is stated that on the Continent many poisonings of cattle, goats, and pigs have been recorded, not infrequently ending in death after two or three days. The Narcissi are strongly narcotic, emetic, and purgative, and cause dilated pupils. Pott states that they cause inflammation of the digestive tract, and convulsions, sometimes with fatal results; and according to Pammel N. poeticus induces intense gastro-enteritis. N. pseudo-narcissus contains the alkaloid Narcissine (C16H17O4N), which with cats causes nausea and purgation (Henry).

Common Fritillary (Fritillaria Meleagris L.). The Fritillary or Snake’s Head occurs only in a few places in England, and truly wild perhaps only rarely in southern and eastern counties—not in Scotland or Ireland. No definite case of poisoning has been found in the literature, but the plant is stated to be poisonous. It contains the bitter alkaloid Imperialine (C35H60NO4), which is a heart poison.

Bog Asphodel (Narthecium ossifragum Huds.) has by some been regarded as a poisonous plant, and Müller says that the poisoning of cows has been recorded, and also that a cat died after drinking the milk of an affected cow. The toxic property is believed to be the glucoside Narthecin.

Molinia caerulea, Moench. A short account by Pott shows that when forming the principal part of moorland pasture grasses, and hence extensively eaten, this grass causes brittleness of the bones of stock, and in sheep chlorosis and wool eating. It also induces hæmaturia, but if free from parasitic fungi (e.g. Claviceps microcephala) and not covered with microscopic, sharp crystals, is quite harmless if only eaten as a secondary or incidental fodder. This grass seems to be very poor in lime (Immendorf, 1898), and Schulze and Castoro found the internodes of the stem to contain a considerable quantity of a pentosan (Xylan). It is poor in nutritive constituents. The harm done is due perhaps in part to this fact, and in part to more or less accidental or occasional constituents (as 0·046 per cent. of lead oxide in a case of the var. altissima near some lead works). Plants said to be occasionally similarly harmful are Juncus sp., Nepeta Glechoma, and Hieracium Pilosella.

CHAPTER VIII
THE EFFECTS OF PLANTS ON MILK.

A number of poisonous plants have a considerable influence on the milk yield of animals which eat them, reducing it in volume or in fat content, or imparting to it an unpleasant flavour which renders it unfit for human consumption, and even affecting the butter made from it. Other plants not actually poisonous also affect milk by “tainting” it, and must therefore be considered harmful otherwise than as mere weeds. Still others affect milk by causing it to be stained with blood, and in some cases the toxic principle of the plant concerned is even stated to have rendered the milk poisonous. It will be useful to give here a brief account of milk-affecting plants, though it is probable that there may be others which are not mentioned.

The plants best known in this connection are the Garlics (Allium oleraceum L., A. ursinum L., A. vineale L., and others), which impart to milk a strong “oniony” flavour. These plants also seriously affect the flesh of animals which eat them, even rendering it unfit for consumption. A case came before the author several years ago in which a considerable number of sheep had eaten a quantity of Allium ursinum, which was growing in a field in which they had been grazing for some days. The meat was so strongly tainted that, as the owner (a butcher) stated, it was quite unfit for sale. The only thing to be done was to pasture the sheep elsewhere for a time.

Pott notes that species of Ranunculus give rise to reddish or bitter milk (Mölkereizeitung, 1897), while Caltha palustris causes loss of milk production in cows.

Ranunculus repens imparts a strong unpleasant flavour to the milk of cows that have eaten it, and the butter made from such milk is distinctly bitter in taste (Güssow).

Ranunculus sceleratus causes a falling-off in milk-yield. (Cornevin.)

Alliaria officinalis Andrz, imparts an oniony flavour to milk.

Achillea Millefolium L. is stated to impart its bitter taste and strong odour to dairy products when eaten by cows. It contains an alkaloid, Achilleine (C20H38O15N2) having a peculiar odour and bitter taste.

Chrysanthemum Leucanthemum has also been suspected of imparting a bad flavour to butter.

According to Pott the milk of cows eating Oxalis Acetosella is with difficulty converted into butter.

The poisonous principle of Colchicum autumnale is stated to find its way into the milk of animals consuming it, and Müller states that the milk of goats which have eaten it has caused the poisoning of infants.

Müller states that a cat died after drinking the milk of a cow suffering from poisoning by Narthecium ossifragum.

Mercurialis annua is said to cause milk to be thin, “blue,” and poor in fat; while in a case already mentioned (p. [68]) M. perennis entirely stopped the secretion of milk.

According to Chesnut, goats may eat quantities of Euphorbia Lathyris, and it is said that their milk then possesses the poisonous properties of the plants. Ingestion of other Euphorbias appears to have the same effect.

Cornevin remarks that Melampyrum arvense is considered to influence cows to produce more milk.

According to some authorities species of Equisetum check milk production or cause it to cease, and E. palustre is stated by Weber to cause the milk of affected cows to become watery, poor in fat, and give rise to a greasy and unappetising butter, while the yield may soon quite fail.

The ingestion of the foliage of the oak (Quercus sp.) is stated by Cornevin to induce Maladie des Bois, with reduction or entire loss of milk production (see p. [69]). Acorns have also affected milk production, and a case is recorded (The Dairy, 1913) in which it is stated that cheese made from the milk of cows which had fed on acorns developed a sharp acid flavour when about four weeks old, though the texture was good. It is not clear, however, how it was proved to be due to the acorns.

In one case recorded a reddish tinge was observed in the milk of a cow suffering from Rhododendron poisoning (p. [46]), and in general reduced milk production appears to occur.

In addition to the foregoing, there is good authority for saying that the following plants may impart a disagreeable flavour to milk, and in many cases the butter made from it:—

Anthemis arvensisL.(Corn Chamomile).
Anthemis CotulaL.(Stinking Mayweed).
Artemisia Absinthium L.(Wormwood).
Conium maculatum L.(Hemlock).
Hyoscyamus niger L.(Henbane).
Matricaria Chamomilla L.(Wild Chamomile).
Pinguicula vulgaris L.(Butterwort).
Senebiera didyma Pers.(Lesser Wartcress).
Sium angustifolium L.(Lesser Sium).
Sium latifolium L.(Water Parsnip).
Tanacetum vulgare L.(Tansy).
Thlaspi arvense L.(Penny Cress).

(See also Index “Milk, plants affecting,” p. [117].)